Mechanical Properties of Khaya and Albizia Films Intended for Pharmaceutical Coating

Abstract

The mechanical properties of khaya and albizia films have been studied to assess their suitability for pharmaceutical coating. The two gums were initially characterized in terms of their physicochemical properties. The mechanical properties evaluated were tensile strength, elastic modulus, and elongation at break, strain and area under the curve (AUC). Films prepared with khaya gum alone were hard, brittle and lacked flexibility while that of albizia were hard, tough, flexible and elastic. Addition of albizia improved the film forming properties of khaya gum and imparted increasing toughness, flexibility and elasticity to the films. Albizia thus appear to be a better film coating material than khaya gum. The hardness of the films was not significantly affected by increase in albizia concentration. Inclusion of HPMC in khaya/albizia blended gels enhanced the film forming, hardness, elasticity, and toughness of the films. HPMC increased the strain values of the films which is predictive of high mechanical performance of the films during coating processes. Albizia and Khaya/albizia film formulations thus have the potential for use in pharmaceutical coating by possessing the requisite mechanical properties of hardness, flexibility and toughness. These essential properties of film coats were greatly enhanced by the inclusion of HPMC in the films. Journal of the Ghana Science Association Vol. 9 (2) 2007: pp. 43-53